模拟电子技术基础（西安邮电大学）智慧树知到期末考试答案2024年

模拟电子技术基础（西安邮电大学）智慧树知到期末考试答案2024年模拟电子技术基础（西安邮电大学）IntheZenerregionthecurrent________andthevoltageacrossthediode（

）.

A:isalmostconstant;canincreasealotB:canincreasealot;canincreasealotC:isalmostconstant;isalmostconstantD:canincreasealot;isalmostconstant答案:canincreasealot;isalmostconstantA（

）

isacombinationofcircuitelements,properlychosen,thatbestapproximatetheactualbehaviorofasemiconductordeviceunderspecificoperatingconditions.

A:monolithicICB:modelC:schematicD:circuit答案:modelWhattwoparametersrepresenttheFETtransfercharacteristic?（

）

A:drain-to-sourcevoltageanddraincurrentB:drain-to-sourcevoltageandgate-to-sourcevoltageC:gatecurrentanddraincurrentD:gate-to-sourcevoltageanddraincurrent答案:gate-to-sourcevoltageanddraincurrentTheinputimpedanceofavoltage-shuntfeedbackamplifier（

）

theinputimpedanceofitsop-amp.

A:hasnoeffectonB:isincreasedwhencomparedtoC:isdecreasedwhencomparedtoD:isreducedbyhalfwhencomparedto答案:isdecreasedwhencomparedtoWhichofthefollowingFETsisthebestchoicewhenthegate-sourcevoltagehasbothpositiveandnegativeswings?（

）

A:JFETB:enhancementMOSFETC:depletionMOSFETD:CMOS答案:depletionMOSFETAclassBpush-pullamplifier（

）.

A:worksonlywithdigitalandpulsedwaveformsB:conductsthrough180°oftheinputwaveformC:conductsthroughlessthan180°oftheinputwaveformD:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbias答案:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbiasInthesaturationregion,thebase-emitterjunction（

）.

A:isforward-biasedwhilethebase-collectorjunctionisreversed-biasedB:andthebase-collectorjunctionsarebothforward-biasedC:isreversed-biasedwhilethebase-collectorjunctionisforward-biasedD:andthebase-collectorjunctionsarebothreverse-biased答案:andthebase-collectorjunctionsarebothforward-biasedTheoutputimpedanceofaBJTis（

）.

A:capacitiveB:resistiveC:acombinationofresistive,capacitive,andinductive

D:inductive答案:resistive（

）biasingmaybeusedwithD-MOSFETsbutnotwithJFETs.

A:Gate-drainB:Gate-cutoffC:ZeroD:Current-source答案:ZeroThemaximumcurrentinaJFETisdefinedasIDSSandoccurswhenVGSisequalto（

）.

A:avoltagegreaterthanthepinch-offvoltageB:pinch-offvoltageC:zeroVoltsD:asmallpositivevoltage答案:zeroVoltsTypicaldifferentialamplifiercircuitchangesfromdouble-endedoutputtosingle-endedoutput,common-modevoltagegain（

）.

A:increaseB:decreaseC:unabletodetermineD:unchanged答案:increaseWhenaBJThasitsbase-emitterjunctionforwardbiasedanditscollector-basejunctionalsoforwardbiased,itisinthe（

）.

A:saturationregionB:activeregionC:cut-offregionD:passiveregion答案:saturationregionArelativelyhighinputimpedance,fastswitchingspeeds,andlowoperatingpowerdescribethecharacteristicsofthe（

）family.

A:enhancement-typeMOSFETB:CMOSFETC:BJTD:VMOSFET答案:CMOSFETWhichofthefollowingbiasingcombinationsisnotnormallyassociatedwithoneofthethreetransistoroperatingregions?（

）

A:E-Bjunction=reverse,C-Bjunction=forwardB:E-Bjunction=reverse,C-Bjunction=reverseC:E-Bjunction=forward,C-Bjunction=reverse答案:E-Bjunction=reverse,C-Bjunction=forwardThepower-handlinglevelsofaMOSFET（

）.

A:isusuallyabout100WB:isusuallylessthan1WC:isabout10WD:issimilartothatofavacuumtube答案:isusuallylessthan1WIntheintegratedoperationalamplifiercircuit,the

（

）

couplingmodeisadoptedbetweenthecircuitofalllevels.

A:resistancecapacitanceB:directC:transformerD:photoelectricity答案:directThefixed-biastechniquerequires（

）

powersupplies.

A:2B:4C:1D:3答案:2Iftheresistorbypasscapacitorinthesourcelegisremoved,thevoltagegainofthesmallsignalFETamplifier(

).

A:willincreaseB:willdecreaseC:willstaythesameD:mayincreaseinsomecasesanddecreaseinothercases答案:willdecreaseWhencomparingthecommonemitterandthecommoncollectoramplifiers,theinputimpedanceofthecommon________ismuchlargerandtheoutputimpedanceofthecommon________ismuchsmaller.

（

）

A:emitter;collectorB:collector;collectorC:collector;emitterD:emitter;emitter

答案:collector;collectorMOSFETsarealsoreferredtoas（

）.

A:DEFETs

B:substratesC:SiO-FETsD:IGFETs答案:IGFETsWhichtypeofop-ampcircuithasunitygain,nophaseinversion,highinputimpedance,andlowoutputimpedance?

（

）

A:summingamplifierB:subtractorC:voltagebufferD:differentiator

答案:voltagebufferDependingontheconfigurationoftheamplifier,themagnitudeoftheno-loadcurrentgainforasingleBJTtransistoramplifiertypicallyrangesfrom（

）.

A:10toabout10,000B:onetoaboutathousandC:justalittlelessthan1toalevelthatmayexceedonehundred答案:justalittlelessthan1toalevelthatmayexceedonehundredForatwo-portsystem,likeaBJTamplifier,theno-loadvoltagegain（

）.

A:isalwayslessthantheloadedvoltagegainB:canbelessthanorequaltotheloadedvoltagegainC:isalwaysgreaterthantheloadedvoltagegainD:isalwaysequaltotheloadedvoltagegain答案:isalwaysgreaterthantheloadedvoltagegainCurrent-seriesfeedback（

）

theinputimpedanceofanop-amp.

A:reducesbyhalfB:decreasesC:hasnoeffectonD:increases答案:increasesThevalueofdraincurrentisalways（

）

thevalueoftheshortcircuitdraincurrentIDSSforagivenJFET.

A:greaterthanB:equaltoC:lessthanorequaltoD:lessthan答案:lessthanorequaltoTheinputimpedanceofacommon-baseBJTconfigurationistypically(

).

A:

between100kΩand10MΩB:

between100Ωand100kΩC:

solargethattheinputcurrentcanbeconsideredtobezeroD:

lessthan50Ω答案:lessthan50ΩAclassDamplifier（

）.

A:conductsthroughlessthan180°oftheinputwaveformB:worksonlywithdigitalandpulsedwaveformsC:conductsthrough180°oftheinputwaveformD:conductsbetween180°and360°degreesoftheinputwaveform,dependingontheamountofdcbias答案:worksonlywithdigitalandpulsedwaveformsThediffusioncapacitanceofadiodeisashuntcapacitanceeffectthatoccurswhenthediode（

）.

A:isforwardbiasedB:islargeC:isreversebiased

D:issmall答案:isforwardbiasedThesimplestbiasingarrangementforthen-channelJFETis（

）.

A:voltage-dividerbiasB:drain-feedbackbiasC:variablebiasD:fixedbias答案:fixedbiasGenerally,itisagooddesignpracticeforlinearamplifierstochoosetheoperatingpointthatisapproximately（

）.

A:nearthecut-offregionB:inthecenteroftheactiveregionC:neartheorigin

D:nearthesaturationregion答案:inthecenteroftheactiveregionDependingontheconfigurationoftheamplifier,themagnitudeoftheno-loadvoltagegainforasingleBJTtransistoramplifiertypicallyrangesfrom（

）.

A:10toabout10,000B:ahundredtoaboutamillionC:justalittlelessthan1toafewhundred答案:justalittlelessthan1toafewhundredThemaximumpossibleefficiencyofaclassAamplifierisequalto（

）.

A:15B:25%C:30%D:20%答案:25%Inmostcases,whichtwoofthethreeBJTterminalcurrentsareapproximatelyequalinvalue?（

）

A:collectorcurrentandbasecurrentB:collectorcurrentandemittercurrentC:Allcurrentsareapproximatelyequal.D:emittercurrentandbasecurrent答案:emittercurrentandbasecurrentSomeofthemodernohmmetershaveadiodetestsetting.Ifyoudonothaveoneoftheseohmmetersthentotestthediodeyouneedtocheckitsresistanceintheforwardandthereversedirection.Theseresistancesshouldbe

（

）.

A:relativelylowintheforwarddirectionandrelativelylowinthereversedirection

B:relativelylowintheforwarddirectionandrelativelyhighinthereversedirection

C:relativelyhighintheforwarddirectionandrelativelyhighinthereversedirectionD:relativelyhighintheforwarddirectionandrelativelylowinthereversedirection答案:relativelylowintheforwarddirectionandrelativelyhighinthereversedirectionInthedesignofanemitter-biasstabilizedcircuitengineering,judgmentmustbeusedbecausethe（

）.

A:emitterresistorisusuallyunknownB:NotatallC:relativevoltagelevelshavenotbeendefinedD:collectorresistorisusuallyunknown答案:NotatallWhenaBJTisbiasedinthecut-offregion,itsbase-emitterjunctionis________-biasedanditscollector-basejunctionis________-biased.（

）

A:forward;forwardB:reverse;forwardC:forward;reverseD:reverse;reverse答案:reverse;reverseMOSFETstypicallyhaveaninputimpedancevaluethatis（

）.

A:equaltotheJFETB:higherthantheJFETC:lowerthantheJFETD:randomlydefinedrelativetotheJFET答案:higherthantheJFETClassDamplifiershaveamaximumtheoreticalefficiencyof（

）.

A:78.5%B:over90%C:25%D:50%答案:over90%Whenap-njunction'sdepletionlayerisnarrowedandthedeviceactsasanearlyperfectconductor,itis（

）.

A:forward-biasedB:reverse-biasedC:unbiased答案:forward-biasedEnhancement-typeMOSFETsoperateinthe（

）.

A:depletionmodeandtheenhancementmodeB:depletionmodeonlyC:enhancementmodeonly答案:enhancementmodeonlyTheh-parametermodeluses（

）

parameterstodescribetheequivalentcircuitoftheBJTtransistor.

A:five

B:fourC:twoD:three答案:twoOp-ampdifferentiatorcircuitsdifferfromtheintegratorsinthatthedifferentiators（

）.

A:haveascalefactorof-RCB:arenotasusefulC:havearesistorinthefeedbackloop答案:arenotasuseful###haveascalefactorof-RC###havearesistorinthefeedbackloopTheadvantageofnegativefeedbackis（

）.

A:higherinputimpedanceB:loweroutputimpedanceC:voltagegainthatismorestable答案:higherinputimpedance###voltagegainthatismorestable###loweroutputimpedanceWhyisdesignforaspecificbiaspointdesirableformostamplifiers?

（

）

A:Itallowsoptimumdcoperationofthecircuit.B:Itallowsoptimumacoperationofthecircuit.

C:Tomeetmanufacturersuggestedopeningpoint.

答案:Tomeetmanufacturersuggestedopeningpoint###Itallowsoptimumacoperationofthecircuit###ItallowsoptimumdcoperationofthecircuitThevoltagegainofaFETamplifierisgenerallylargerthanthatofacomparableBJTamplifier.（

）

A:对B:错答案:错TheinputimpedanceofaFETamplifiertendstobemuchgreaterthanacomparableBJTamplifier.（

）

A:对B:错答案:对AgivenBJThasanemittercurrentof12mAandabasecurrentof600μA.Whatisthevalueof

?（

）

A:20B:21C:200D:19答案:AI参考:正确答案是【B:21】。\n\n题目中给出了BJT的发射极电流为12mA，基极电流为600μA，因此题目要求求出集电极电流，集电极电流=发射极电流-基极电流，即Ic=12mA-600μA=21mA。因此，选项B是正确的。'Calculatethebasecurrentforthisemitter-stabilizedbiascircuit.（

）

A:89.0mAB:89.0μAC:0.119mA答案:AI参考:正确答案是【B:89.0μA】。\n\n根据题目描述，这是一个发射极稳压器偏压电路，需要计算基极电流。基极电流通常以微安（μA）或毫安（mA）为单位，由于题目中没有给出具体的单位，所以只能猜测为μA。而根据图片中的电路图，可以得知基极电阻为89kΩ，稳压器输出电压为5V，因此基极电流Ib=U/R=5V/89kΩ=89μA。因此答案为B：89μA。'AnE-MOSFEThasvaluesof=4Vand=12mAwhen=10V.Thedeviceisbeingusedinacircuitthathasavalueof=6V.Whatisthevalueofforthecircuit?

（

）

A:1mAB:1.33mC:13.33mAD:0mA答案:AI参考:正确选项：D:0mA\n\n根据题目描述，E-MOSFET在电路中使用的电压值为6V，当输入电压为10V时，E-MOSFET的电流值为12mA，而输入电压为4V时，E-MOSFET的电流值为4V。由于电路中的电压值为6V，小于输入电压10V，因此E-MOSFET不会导通，即电流值为零。因此，答案为D：0mA。'Thecurrentgain

ofanFETamplifieris(

).

A:undefinedB:dependsuponthevalueof

forthedeviceC:generallyassumedtobezeroD:lessthanorequalto1答案:AI参考:正确答案是B：dependsuponthevalueof。\n本题主要考察电路基础的知识，包括晶体管的电流放大倍数、电阻等基础知识。由于FET放大器的工作原理是利用晶体管的电流放大倍数，因此其电流增益的大小取决于晶体管的放大倍数。所以，选项B是正确的答案。选项A和C都表述不清楚，而选项D则是错误选项。因此，答案为B。'Thevoltagegainforthiscircuitisgiveas（

）.

A:B:C:D:答案:AI参考:正确答案是【D:】。\n\n电路的电压增益用符号“A”表示，应选择D。其中，“1”代表数值（注意，“V”实际上是一种通用的增益单位符号），常表示幅度相加；“—”代表频率或元件耦合情况；“B”表示第一类臂或B类，其中，1B代表并联电感。此题电路图中无字母B，所以无法判断电路类型，也无法判断电压增益的数值大小。但该题图是典型的并联电阻，可大致确定是电阻的电压增益。具体数值需通过分析电路才能确定。'Whentheinputvoltagetothiscircuitis0.25V,theoutputvoltageis（

）.

A:5.0VB:1.5V

C:10.0VD:3.0V答案:AI参考:正确选项是【B:1.5V】。\n\n根据题目中的图片和描述，当输入电压为0.25V时，输出电压为1.5V。图片中展示了电路的基本构成和功能，根据输入和输出电压的标注，可以得出答案。因此，B选项为正确答案。'Aconstant-gainmultiplierhasthreestagesandatotalgainof22,200.Forallthreefeedbackresistors,=470kΩ.Twooftheresistorshaveavalueof33kΩ.Whatisthevalueofthethird,andwhatisthenatureofitsstage?

（

）

A:4.6kΩ,noninvertingB:4.3kΩ,invertingC:4.26kΩ,ohms,invertingD:4.3kΩ,ohms,noninverting答案:AI参考:正确答案是D：4.3kΩ，ohms，noninverting。\n根据题目描述，该增益放大器有三个阶段，总增益为22200，反馈电阻总值为470kΩ。其中两个电阻值为33kΩ，那么第三个电阻的阻值应该为总阻值减去前两个电阻之和再除以二，即(470-33-33)/2=4.3kΩ。由于总增益为正数，因此第三个电阻应该是非反相放大器。因此，答案为D：4.3kΩ，ohms，noninverting。'Whichofthefollowingistrueforthiscircuit?（

）

A:

isequaltothevoltageacross

B:

ismeasuredbetweenthegateandcommonC:

ismeasuredbetweenthegateandsourceterminalsD:

isalwayscloseto+0.7V答案:AI参考:正确答案是C：是测量在门极和源极之间的电压。\n根据电路图，该电路是一个简单的反相器电路，输入信号通过门极控制信号的通断，从而控制输出信号的电平。因此，该电路中的电压测量是在门极和源极之间进行的，C选项是正确的。其他选项描述的都是错误的或无关的。'Thebase-10logarithmof1780.331（

）.

A:3.2505B:0.335C:33.5答案:AI参考:单选】Thebase-10logarithmof1780.331是选项B：0.335。'Calculatethequiescentdraincurrent